> For the complete documentation index, see [llms.txt](https://swatplus.gitbook.io/io-docs/llms.txt). Markdown versions of documentation pages are available by appending `.md` to page URLs; this page is available as [Markdown](https://swatplus.gitbook.io/io-docs/introduction-1/basin-1/parameters.bsn/uhyd_alpha.md).

# uhyd\_alpha

This parameter is required if [*uhyd*](/io-docs/introduction-1/basin-1/codes.bsn/uhyd.md) = 1.